Various windows and glass doors have been developed in an effort to avoid the type of structural damage that may result from high winds, as may be experienced in a hurricane. For example, as a result of the widespread destruction caused by hurricane Andrew, new standards have been proposed in certain southern Florida counties to provide stronger windows and doors to decrease the damage to associated structures during severe storms. The glass used in wind resistant windows and doors is typically a laminated glass panel and includes at least one plastic reinforcing layer and one or more glass layers.
The new standard basically requires that the glass panel of the window or door absorb a first blow from an end of a wood 2.times.4 (weighing 9 lbs.) striking the center at 34 miles per hour. A second similar blow is directed to a corner area of the glass panel. Consequently, the glass is cracked but a large portion of the glass panel is retained in position to close the opening by a reinforcing plastic layer. Only a relatively small effective opening may be formed in the cracked glass panel by the 2.times.4 strikes. The window or door is next subjected to a pressure cycling test where positive and negative pressures are applied sequentially. A typical test would be 9,000 cycles of 75 lbs./sq. foot and -80 lbs./sq. foot. Positive indicates that the pressure is greater on the exterior of the window or door, and negative pressure indicates that the pressure on the interior of the window or door is greater. During the pressure cycling testing, the plastic film and glass in the glass panel becomes a sail and can exert relatively large forces on the window or door sash and frame members.
Unfortunately, if the window or glass door fails completely, pressures can be generated internal to the structure that may be sufficiently high to cause damage. For example, a portion or all of the roof may be blown from the structure. High quality windows and glass doors, such as those offered by Pella, for example, typically include a wood frame and wood sash and an exterior aluminum cladding material. The wood frame and sash are especially attractive, and can be shaped and painted to achieve a variety of pleasant designs.
However, the possibility of a wood window or wood glass door failing is further enhanced because the wooden styles and rails of the sash, for example, are typically relatively thin. Thus, the problems with addressing the above mentioned hurricane standards are especially difficult for high quality wood windows and wood glass doors. The respective styles and rails may flex, thereby increasing the wind-induced movement of the already cracked glass panel until the wood styles and rails fail or come completely loose from the structure. Sliding glass doors present an especially difficult challenge because of the relatively large surface area, and typical mounting arrangements of the door panels.